I completed my V3.0 board and stim build and had been having problems with no RPMs and no TPS response with the stim, also no LED flash. Everything else was working ok. I had adjusted my pots and also reviewed the build steps to make sure all of the components were in place, good solder joints, etc. I had forgotten one important step....cleaning off all the solder flux residue after the build. I went ahead and cleaned the residue with isopropyl alcohol, let it dry, plugged it into Megatune, and Voila!...everything works!...RPMs, LED flash for f. pump, warm up, injectors, spark, accel enrich, etc. Very happy dude here!


Don't forget to clean your flux everybody!

 

Good advice on cleaning the board.
I used to do a lot of surface mount soldering, like manually with a microscope and tweezers. There were always a few solder ***** floating around in the flux even when I used wire solder (instead of the syringe of solder paste). I think it happens when the hot tip boils the flux and causes some spatter. These little ***** are easy to miss with naked eye and can bridge pins on components. There is a product called "flux off" but it is expensive for just being a can of solvent. Alcohol and an old tooth brush does the trick.

 

I remember seeing those "solder *****" from spatter for sure....it may have been more of the culprit than the flux itself.